Re: Completion

[Stephen Leake <stephen_leake@stephe-leake.org>]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>>> +if there is one match, but it's not an exact match, the function
>>> +should return the match;
>>
>> Actualy, when there is one match, "the common substring of all matches"
>> is that match, so I think we can make it simpler, e.g.:
>>
>>     This specifies a @code{try-completion} operation.  The function should
>>     return @code{t} if the specified string is a unique and exact match;
>>     It should return @code{nil} if there are no matches; and it should
>>     return the longest common prefix of all matches otherwise.
>
> Yes, that seems clearer.
>
>> What if the user writes the whole name by hand: how do you get the ID in
>> this case?  In my experience, the need to handle that "manual case" most
>> of the time ends up covering just as well the case where the user
>> selected an entry from the *Completions*.
>
> Oh, I didn't even consider that the user may type the name.  Yeah,
> you're right; returning the text properties wouldn't really be generally
> useful here...

I had a similar problem completing on names in an Ada buffer; names can
be overloaded, so just the name is not unique.

So I included the line number with the name in the completion table;
each entry looks like:

foo<1>
bar<10>
foo<20>

The user sees those strings, and can complete on the line number to pick
the instance of an overloaded name.

Then the code can retrieve the line number from the completed string.

If the user types the name without completing, you're out of luck (my
code throws an unhelpful error). But that never happens in practice,
since completion works so nicely.

I use icomplete-mode, with completion options set so I have to type C-j
to get out of a completing read with non-matching text.

This code is in a development version of ada-mode; available via email
on request.

For IMDB, you could use | to separate fields, and complete on
filmname|year|actor1|...

Whether the user will ever or often enter text without completing
depends on the use case; finding function names in source code is a much
smaller problem than finding films in IMDB.

-- 
-- Stephe